Fighting the fat

Fats, oils and grease (FOG) are responsible for more than half of all sewer blockages in the UK. But a new trial could change the way FOG is managed. Aziz Tejpar of Environmental Biotech International reports

A step away from fatty foods and a health-kick designed to get us in shape is exactly what Anglian Water and Environmental Biotech are planning - but with drains not waistlines.

Anglian Water is conducting a two-year trial at Baddow Road in Chelmsford,
Essex, which could change the way fats, oils and grease (FOG) is managed regionally and nationally. The trial is in conjunction with Chelmsford Borough Council, the Water Research Council, and Environmental Biotech.

Fat has become the enemy of water authorities throughout the UK. Thousands of FOG-related sewer spills occur every year, and Anglian Water is certainly no exception. An estimated 55% of sewer blockages result directly from incorrect FOG disposal. Consequently, the UK water industry spends about £20M a year cleaning up to reduce the risk of sewer flooding.

Many of these problems stem from the disposal of waste foods from restaurants and fast-food outlets. Major problems occur when FOG builds up in the drain lines below a property. This causes pipes to occlude, with solids attaching to the fat resulting in blockages and sewer overflows. When fat hardens, chunks break off and flow down the pipe, which can jam in the machinery of underground pumps. This can cause a municipal heart attack, resulting in particularly nasty sewer overflows and expensive call outs.

Baddow Road, which is home to around 20 food outlets including restaurants, takeaways, fast-food shops and cafeterias, is a prime example of this type of problem. Unfortunately for the surrounding shops and pedestrians, the 457mm sewer pipe that runs beneath is clogged solid with FOG on a far too regular basis, costing Anglian Water an estimated £10,000 a year.

With problems on the increase, not just in Chelmsford, but across the UK, Anglian Water will be testing a whole range of technologies, with the first being an extensive trial of Environmental Biotech's bioremediation-based technology.

Gary Collins, collection manager for Anglian Water, says: "Now that we have got the support from businesses in and around the Baddow Road area, the first step in the trial will involve using the bacteria produced by Environmental Biotech. The bacteria are simply added to the sewer where they eat the FOG before consuming themselves."

Aziz Tejpar, managing director of Environmental Biotech explains the process further: "There are a number of companies purporting to offer biological-based solutions to FOG problems. But they have met with a mixed response and are not without their limitations. Unlike the majority of enzyme-based solutions currently available, Environmental Biotech's bacterial two-phase action has made all the difference to professional perceptions of what biological solutions can offer.

Enzymes, solvents, and surfactants simply move the grease problem further down the line, where the blockage will repeat itself.

"Our technology, on the other hand, remediates grease problems for good, hence the terminology 'bioremediation' - a natural process in which bacteria actually consume grease and oil from drain lines, grease traps, and interceptors. The FOG molecules consist of fatty acids attached to a glycerol backbone. The enzymes break down the bonds that hold the grease molecules together. And the bacteria eat the components, reducing them to carbon dioxide and water. These bacteria are non-toxic, non-pathogenic, live, and vegetative, and are simply drip-fed at regular intervals into the problem area. Dosing systems, controlled by a timer mechanism, release the live vegetative bacteria routinely into the offending areas via plastic stilling chambers.

During each bi-weekly visit, a technician examines the dosing arrangements and replenishes the bacterial solution, which digests the hydrocarbon-based compounds of the FOG, reducing it to carbon dioxide and water. This will hugely reduce the amount of FOG entering the 457mm sewer at Baddow Road, with discharge rates expected to be significantly below the standard rate of 300mg/l.

"In fact, the technology is already used by 272 ASDA stores and a growing number of McDonald's restaurants across the UK, allowing considerable savings to be made on tankering at the same time as saving the environment."

But, unfortunately, companies responsible for disposing of FOG tend to adopt reactive drain line management measures. This is one of the reasons why Anglian Water has decided to conduct the trial with a number of restaurants along Baddow Road that want to help improve the situation not just for themselves but for others too.

Gary Collins says: "Installing grease traps and reacting to blockages are not enough. Encouraging those responsible to participate in preventative drain line management is desperately needed. And I hope the trial makes those responsible take the necessary actions to alleviate FOG.

"The main aim is to solve problems before they occur. After all, preventing a drain backup is far better than dealing with it after it has blocked, overflowed and caused major inconvenience. Water companies are quite within their right to fine or even prosecute culprits," he says.

"But it's an expensive exercise and one that does not make commercial or environmental sense for either the water company or the business in question.

Educating businesses on responsible drain line management instead of issuing fines has to be the way forward," he adds.

The trial will comprise an educational programme designed to encourage companies to take immediate action. Gary Collins says: "Anglian Water and Chelmsford Borough Council have already started the process of visiting local business owners in the area, reminding them that they have a responsibility to keep their sewers clean.

We have experienced a positive reception so far and have every reason to believe that the trials will be a huge success."

The educational programme will inform businesses of:

Legal issues including relevant national and local regulations and legislation

Sociological issues including best grease management practice with educational campaigns

Technological solutions with a comparative trial of different biological and chemical FOG treatments, with recommendations for the most effective technology

Engineering and operations issues relating to best operational practice and educating employees of safe use of technology

The aim will be to publicise the results and set a benchmark for others to follow suit. But, unlike the case with the restaurants along Baddow Road, many restaurateurs are complacent about FOG issues and are more than happy to deal with a problem after it has happened.

Businesses simply do not realise the cost-savings to be made from the installation of a suitable and reliable preventative drain line management system. For example, on trials at four separate McDonald's restaurants from April to June 2005, bioremediation not only cleared up any FOG problems, it saved the company over £15,000 through the reduction of reactive call-outs in just three months. Of course, not all restaurants are as big as McDonald's or suffer from the same amount of FOG build-up, but the principle is the same. Without some sort of preventative measures in place, drainage problems are hitting bottom line profitability hard, not to mention the environment.

It is envisaged that at the end of the Baddow Road trials, participants will see this for themselves with an improvement in the function of the local sewer system with less blockages, sewer flooding incidents and odour complaints in the area.